Self-propelled or powered wheelchairs have vastly improved the mobility/transportability of the disabled and/or handicapped. Whereas in the past, disabled/handicapped individuals were nearly entirely reliant upon the assistance of others for transportation, the Americans with Disabilities Act (ADA) of June 1990 has effected sweeping changes to provide equal access and freedom of movement/mobility for disabled individuals. Notably, various structural changes have been mandated to the construction of homes, offices, entrances, sidewalks, and even parkway/river crossing, e.g., bridges, to include enlarged entrances, powered doorways, entrance ramps, curb ramps, etc., to ease mobility for disabled persons in and around society.
Along with these societal changes has come an opportunity to offer better, more agile, longer-running and/or more stable powered wheelchairs to take full advantage of the new freedoms mandated by the ADA. More specifically, various technologies, initially developed for the automobile and aircraft industries, are being successfully applied to powered wheelchairs to enhance the ease of control, improve stability, and/or reduce wheelchair weight and bulk. For example, sidearm controllers, i.e., multi-axis joysticks, employed in high technology VTOL and fighter aircraft, are being utilized for controlling the speed and direction of powered wheelchairs. Innovations made in the design of automobile suspension systems, e.g., active suspension systems, which vary spring stiffness to vary ride efficacy, have also been adapted to wheelchairs to improve and stabilize powered wheelchairs. Other examples include the use of high-strength fiber reinforced composites, e.g., graphite, fiberglass, etc., to improve the strength of the wheelchair frame while reducing weight and bulk.
One particular system which has gained widespread popularity/acceptance is mid-wheel drive powered wheelchairs, and more particularly, such powered wheelchairs with independently driven and controlled drive wheels. Mid-wheel powered wheelchairs are often designed to position the drive wheels, i.e., the rotational axes thereof, slightly forward of the overall Center Of Gravity (COG) of the occupant and wheelchair to provide enhanced stability and maneuverability. Further, the ability to independently control the speed and torque of each wheel vastly improves the maneuverability, particularly in the yaw axis, of powered wheelchairs. That is, the drive wheels may be driven in opposite directions to enable yaw or heading changes with essentially a zero turn radius. The wheelchair, therefore, can turn within very confined areas and at essentially double the rate. Such mid-wheel powered wheelchairs are disclosed in Schaffner et al. U.S. Pat. Nos. 5,944,131 & 6,129,165, both commonly assigned to Pride Mobility Products Corporation of Exeter, Pa.
While such wheelchair designs have vastly improved the capability and stability of powered wheelchairs, designers thereof are continually being challenged to examine and improve wheelchair design and construction. While these are all welcome advances, they also necessarily add weight and complexity to the vehicle.
Contemporary powered wheelchairs, which may include as many as three power supply units (e.g. batteries), a seat, footrest, a main structural frame, drive train assembly other sundry items, can weight several hundred pounds. It will be appreciated, therefore, that even the most physically able individual will require some form of assistance when transporting a powered wheelchair to another destination. In an effort to ameliorate the transportability of such powered wheelchairs, various efforts have been made to augment the lift capacity for the wheelchair user. Perhaps the best known examples are those which are used in combination with a ramp or elevator for rolling or lifting the wheelchair into a vehicle. These “powered-lift systems”, as one may readily appreciate, are expensive and are limited in use on vehicles of sufficient size to accommodate the assembled wheelchair and the hydraulic or pneumatic lifting equipment.
Other wheelchairs employ folding frames or removable assemblies in an effort to reduce their weight and/or bulk. As such, these wheelchairs may be stowed and transported in vehicles having a smaller payload capacity. While these wheelchairs have improved the transportability, they typically require the disassembly of multiple components, e.g., fasteners, pins, C-rings, clamps, etc., to yield individual assemblies of appropriate size and/or weight. Alternatively, other designs require the use of special tools to “break-down” or fold the various wheelchair components.
Kramer, Jr. et al. (U.S. Pat. No. 6,220,382) discloses a wheelchair having a separable frame which requires the breakdown of as many as eight separate elements. These designs do not always facilitate rapid disassembly and/or reassembly and, furthermore, create an unwelcome opportunity to misplace, omit, or improperly install smaller assembly items.
A need, therefore, exists to provide a transportable wheelchair which (i) permits assembly and disassembly in a rapid and expeditious fashion, (ii) minimizes the number of assemblies, (iii) eliminates the potential for omission of smaller parts or improper reassembly, and (iv) enhances the ability to handle/manipulate subassemblies.